where \(n\)  is a positive integer (see e.g. [1]}). When the coupling is weak, or \(h<<1\) , the smallest possible value of \(n\)  corresponds to the strongest resonance. Despite that parametric resonances were obtained by adopting an ansatz for the frequencies coupling it was demonstrated that they are a mathematical property of thin, nearly Keplerian disks [2]}, [3]}, [4]}.
